Way guard structure



March 18, 1947. ARWTAGE 2,417,672

WAY GUARD STRUCTURE 4 Sheets-Sheet r 1 Filed July 27, 1944 INVENTORBiOSEPH B; 'ARMITAGE ATTORNEY March 18, 1947.

J. B. ARMITAGE WAY GUARD'STRUCTURE Filed July 27, 1944 4 Sheets-Sheet 3FIG.

Ill/Ill IIIIl/IIIIIIIII/I/IJ INVENTQR JOSEPH B. ARMITAGE- BY flfi wATTORNEY March 18, 1947. ARM| TAGE I 2,417,672

WAY GUARD STRUCTURE Filed July 27, 1944 4 Sheets-Sheet 4 INVENTOR JOSEPHARMITAGE .fl fl'hm Ill'llll ma s n ATTORNEY Patented Mar. 18, 1947 WAYGUARD STRUCTURE Joseph B. Armitage, Wauwatosa, Wis., assignor to Kearney& Trecker Corporation, West Allis, Wis., a corporation of WisconsinApplication July 2'7, 1944, Serial No. 546,833

22 Claims.

This invention relates, generally, to improvements in way guards andmore particularly to an improved way guard structure adapted to preventthe deposit of chips or other injurious foreign matter upon theaccurately finished ways that form the bearing surfaces for the movablework supporting element of a machine.

A general object of the invention is to provide a way guard structurethat comprises an improvement over applicants copendin application,Serial No. 497,034, filed August 2, 1943.

Another object of the invention is to provide an improved way guardstructure arranged for unitary application to the base of a machine.

Another object of the invention is to provide improved way guardstructures, each including a strip of flexible material adapted forattachment to one of the opposite ends of the movable work support andmovable therewith in a man-' her to protect the portions of the ways notcovered by the movable work support.

Another object of the invention is to provide an improved way guardstructure including a flexible way guard strip trained about a pluralityof fixed and movable support and guide members arranged in such a mannerthat the inactive portion of the strip follows a path of reverselydirected spaced flights and is yieldably maintained extended at alltimes so that the contaminated surface of the strip is never permittedto contact the surface of the strip that forms the protective coveringfor the normally exposed portions of the ways of the machine.

Another object of the invention is to provide an improved way guardstructure, including compensating mechanism arranged in a manner toyieldably retain the way guard in extended taut condition at all times,while permitting movement thereof in response to movement of the worksupport to provide the desired protective covering for the ways of themachine, regardless of the position of the work support along the ways.

Another object of the invention is to provide a unitary way guardstructure adapted for attachment, to the end of the bed of the machineand constructed in a manner to permit overtravel of the work supportingelement beyond the ends of the ways.

Another object of the invention is to provide an improved way guardstructure adapted for unitary application to each end of the machine andincluding coupling means operative in a manner to permit the unitaryaction of the compensat ing mechanism disposed at opposite ends oi themachine to effect the retraction of the way guard attached to theleading edge of the movable work support at the same rate at which thetrailing way guard is being paid out under the action of the moving worksupport.

A further object of the present invention resides in the provision of aplurality of unitary way guard structures arranged for attachment to theopposite ends of the bed of the machine and each including a flexibleway guard strip, a plurality of way guard guiding and supporting memberscarried by the frame of the way guard structure and adapted to directthe course of travel of the flexible way guard member along a pluralityof spaced reversely directed paths; a movable unit mounted in the framefor supporting some of the way guard guide and supporting members; andmeans for yieldably urging the movable unit away from the fixedlymounted way guard support and guide members, whereby the flexible wayguard member is constantly retained in extended taut condition.

According to this invention, an improved way guard structure of unitaryform, including a flexible way guard strip, disposed to cover thenormally exposed portions of the ways, is adapted for'application to thebed of the machine to provide ample protection against the deposit ofchips or other injurious foreign matter upon the relatively soft andaccurately finished ways of a machine. In some instances, a singleflexible way guard strip of sufficient width to cover both of theparallel machine ways may be employed. In other instances, it may beadvantageous to utilize separate strips to affordprotection for theindividual-ways. In any event, one end of each flexible way guard stripis anchored within the way guard structure and its remaining or free endis arranged for attachment to one end of the work support that ismounted for sliding movement along the ways of the machine. Theintermedlate portion of each flexible way guard strip is guided andsupported by a plurality of fixed and movable members over which the wayguard is trained in a manner to provide a plurality of spaced reverselydirected flights arranged to retain the contaminated surface free fromcontact with the remaining surface of the guard. The movableway guardsupport and guide mem bers are-mounted to permit their unitary move mentin response to movement of the work support and yieldable means servestoretainthe way guard extended and taut at all times. As themov'able worksupport is reciprocated under power through controlled cycles ofmovement, the way guard attached to its trailing edge is advanced andthe way guard attached to its leading edge is retracted. The yieldablemeans, attached to the unit carrying the movable way guard support; andguide elements, serves as a compensating mechanism, which functions inresponse to movement of the work support to permit the individual wayguards to be paid out or retracted. As indicated in the forms of theinvention illustrated in the accompanying drawing, the compensatingmechanisms disposed at opposite ends of the bed in the unitary way guardstructures may be harnessed together to work in unison, or they mayfunction independently. The independent operation of the compensatingmechanism is particularly advantageous in instances where the worksupport is permitted suificient movement to overtravel the end bracketsor housings containing the way guard structures.

The foregoing and other objects of the invention will become more fullyapparent from the following detailed description and may be achieved bymeans of the exemplifying apparatus depicted in and set forth in thespecification in connection with the accompanying drawing, in which:

Figure 1 is a vertical longitudinal sectional view through the base of amilling machine, showing a way guard structure constructed in accordancewith the teachings of the present invention;

Figure 2 is a top plan view of the structure shown in Figure 1 andhaving parts broken away to more clearly illustrate certain structuralfeatures of the invention;

Figure 3 is an enlarged vertical transverse sectional view, takensubstantially along the plane of the line 33 of Figure 2 and showingmore particularly the unit that carries the movable way guard supportand guide members, together with means for guiding the path of travel ofthe movable unit;

Figure 4 is an enlarged fragmentary vertical longitudinal sectionalview, taken substantially along the plane of the line 4-4 of Figure 3and having parts broken away to more clearly illustrate certainstructural features of the invention;

Figure 5 is an enlarged fragmentary vertical longitudinal sectional Viewthrough the ends of a milling machine base provided with way guardstructures embodying a modified form of the invention;

Figure 6 is an enlarged fragmentary vertical transverse sectional View,taken substantially along the plane of the line 66 of Figure 5 andhaving parts broken away to more clearly illustrate certain structuralfeatures of the form of invention there shown;

Figure '7 is an enlarged fragmentary horizontal sectional view, takensubstantially along the plane of the line 'l---! of Figure 5 and showingthe guide rail and mounting bracket for the movable way guard supportingmembers;

Figure 8 is a fragmentary end elevational view of the base of a millingmachine provided with another modified form of way guard structure andhaving parts broken away to more clearly illustrate the use ofindividual guards for the separate ways;

Figure 9 isa fragmentary vertical longitudinal sectional view throughthe structure illustrated in Figure 8 and showing an arrangement ofparts which permits overtravel of the movable work support beyond theend of the base of the machine; and

Figure 10 is a fragmentary top plan view of a portion of one end of themachine illustrated in Figure 8 and showing a unitary way guardstructure with parts broken away to more clearly disclose thearrangement of its cooperating elements.

Accuracy of production on machines including a reciprocating worksupporting element mounted for sliding movement along ways formed on thebase is dependent upon the continuing accuracy of the finish of theways. The invention herein set forth presents improved way guardstructures constructed in a manner to provide ample protection for theways of the machine, to insure against the deposit of chips or otherforeign matter upon the normally unprotected portions of the ways. Themaintenance of the ways in clean condition, without mars or scratcheswhich normally result from the accumulation of chips or other foreignmatter on the way surfaces over which the table is being constantlyreciprocated, gives continued aczuracy and added life to the machine.

Referring to the drawing, the several forms of the improved way guardstructure embodying the teachings of the present invention are shown inconjunction with a milling machine. It will be noted that the machinecomprises a base or bed 49 having a pair of horizontally disposedparallel guide ways i I upon whch a work support or table I2 is mountedfor sliding movement. The table I2 is provided with a feed screw i3,rotatably mounted in a pair of end brackets It, secured to the oppositeends of the table. A cooperating driving nut 15 is mounted in the baseill in the usual manner so that relative rotation between the screw I3and nut 15 effects longitudinal displacement of the table I2 along theways I i. Operation of the szrew and nut mechanism to move the table l2along the ways ll may be effected in the usual manner, either manuallyor by means of a power transmission mechanism (neither of which isshown) located in a central compartment It within the base It).

Referring more particularly to the form of the invention shown inFigures 1 to 4, inclusive, of the drawing, it will be noted thatidentical way guard receiving structures 20 are applied to each end ofthe base Iii. Each way guard structure 29 comprises a frame 2| in theform of a housing provided with side marginal flange portions 22 adaptedto receive anchor bolts 23 (see Figure 2) by which the frame members aresecured to the ends of the base ill. The frame member 2| provides ahousing adapted to contain and support the way guard structure of thepresent invention. The frame member 2! is provided with a transverselyextended horizontal slot 2 adapted to provide an opening through which astrip 25 of flexible way guard material may be passed. A plurality ofway guard guide and support members, preferably in the form of rollers25, 21 and 28, are mounted in substantial vertical alignment in theframe 2! and are respectively journalled for rotation in suitablebearings positioned and retained by bearing caps 23, in the manner shownin Figure 4. The frame 2|; also includes a pair of horizontally disposedtrack or guide rails 38, extending into the open end of the bed I9, andeach disposed to lieadjacent to a side wall of the bed iii, to which itmay be secured by suitable anchoring bolts. The guide rails 30 serve asspaced supports for a movable unit that includes a pair of arms 3| inwhich a plurality of rollers 32, 33 and 34 are. each rotatably mountedin spaced relationship in suitable trunnions orbearings. The shaft ofthe center roller 33 extends outwardly beyond the arms 3| and its endseach receive a roller bearing 3'1, releasably retained thereon by a snapring 38. The bearings 31 ride within the guide rails 30 which are ofchannel form and serve to support the unit that includes the bank of wayguard guide rollers 32, 33 and 34, in its movement toward and fromthestationary rollers 26, 21 and 28.

A suitable harness 40 is attached to each of the connecting arms 3 I,aboveand below the intermediate roller 33. The harnesses 40 are arrangedto be connected in pairs, one adjacent each side of the base [0, bymeans of cables 4| directed over separate sets of pulleys 42 and 43,positioned in a manner such that the cable is passed through the lowerportion of the compartment It, so as not to interfere with the usualpower transmission mechanism contained therein. A coil spring 44 isincorporated in each of the cables 41 for the purpose of constantlymaintaining tension upon the harnesses 46 to yieldably urge the movableunits, including the way guard rollers 32, 33 and 34, away from thestationary rollers 25, 2'! and 28, so as to maintain the way guardstrips 25 in extended taut condition at all times. The coil springs 44are so arranged that they exert a balanced tension on each of themovable units disposed at opposite ends of the machine, so that theunits will move evenly along the guide rails 31!.

With reference to Figure 1, it will be noted that the table I2 is shownin an extreme position at the lefthand end of the bed It! wherein themovable unit carrying the support and guide mecha nism for the way guardstrip 25, associated with one end of the table, has been retracted toits inner extreme position to take up the unused portion of the wayguard strip. The movable unit carrying the support and guide means forthe way guard strip connected to the other end of the table is disposedin its outer extreme position, wherein it lies adjacent the stationaryrollers 26, 21 and 28. As the table 52 is moved toward its other extremeposition at the righthand end of the bed, the two way guard support andguide mechanisms will each be moved to positions which are the reverseof those illustrated in Figure 1 of the drawings. The coil springs 44serve, at all times, to draw the movable units carrying the way guardsupport and guide mechanisms toward each other, so that the way guardstrips 25, attached to each end of the table I 2, are always retained inextended taut position, with their active portions disposed to form aprotective covering for the portions of the ways If that are not coveredby the table [2.

The form of invention shown in Figures 1-4, inclusive, is particularlywell adapted for use in machines having a relatively long bed, thehollow end portions of which provide adequate space for the receipt ofthe movable way guard support and guide members.

A modified form of the invention is illustrated, in Figures 5, 6 and '7of the accompanying drawing, wherein the way guard support and guidemechanism is completely contained within a housing arranged forattachment to the end of the bed ID in any suitable manner. While themodified form of invention shown in these figures partakes generally ofthe characteristics of the previously described form, it should benoted.

that'the movable way guard support and guide members are arranged formovement in a vertical plane and wholly Within the confines of thehousing 50. One purpose of this arrangement lies in the fact that thelength of the bed is not a controlling factor in the organization of theway guard structure. Since the structure is self-contained, the size ofthe housing 50 may be modified in accordance with the required length oftable travel so that the amount of movement of the unit carrying themovable way guard support and guide members multiplied by the number ofreversely directed flights of the way guard is equal to or greater thanthe maximum distance of table travel. In this form of invention, one endof the way guard strip 25 is attached to the end bracket M on the table[2, by means of a clamping bar 5|, arranged to be bolted against theouter surface of the end bracket [4, to secure the way guard strip indesired position, above the way to be protected. The housing 50 isprovided with a horizontally disposed opening 52, through which the wayguard strip 25 may be threaded. A suitable wiper element is positionedon the end bracket 50 in a manner to contact the top surface of the wayguard strip as it passes through the opening 52 to effect the removal ofloose material from the contaminated surface of the way guard strip. Theway guard strip is then passed over a roller 53, journalled for rotationin suitable bearings mounted in a flange portion 55 of the housing 50.The way guard strip 25 is then directed over additional guide andsupport rollers 55, 51 and 58 and arranged to have its free end anchoredto the housing 50 by the application of a clamping bar 59. The roller 51(see Figure 6) is journalled for rotation in bearings mounted in theflange 55 in a manner similar to that described for the roller 53. Therollers 56 and 58 are journalled in laterally spaced relationship insuitable bearings mounted in ears formed on each of a pair of yokes 60,which form a movable unit for supporting the rollers 56 and 58. Each ofthe yokes 60 is provided with a pair of vertically spaced guide rollers5| mounted to extend outwardly therefrom and arranged to be received andguided in channel members 62 secured in upright position on the sidewalls by means of anchor bolts 63. As in the previously described formof invention, the movable units, including the way guard support andguide rollers 56 and 58, disposed at opposite ends of the machine, arearranged to be connected by means of a pair of cables 61, each includinga tension spring .58, which serves to maintain the way guard strips 25in extended taut condition. The cables 51 are anchored in any suitablemanner to each of the yokes 55 and are trained about guide pulleys 69mounted on the side walls adjacent the bottom of the housing 50 so thatthe cables 61 and springs 68 will not interfere with the power drivingmech anism contained in the central hollow portion of the bed H1.

The particular advantage of the modified form of the invention shown inFigures 5, 6 and 7 resides in the fact that the way guard structure iswholly contained within the housing 50 to provide a unitary structurearranged 'for attachment to the end of the bed of the machine. With theway guard structure self-contained within the housing 50, the length ofthe bed of the machine is relatively unimportant, since none of the wayguard-structure extends into that portion of the machine and, hence, thestructure may readily be applied to machines wherein the overall lengthof the base would normally be insufllcient to properly accommodate theway guard structure shown in Figures 1 to 4, inclusive.

A further modified form of the invention is disclosed in Figures 8, 9and of the accompanying drawing. This modified form differs from thepreceding forms in two ways. The single way guard strip 25, previouslydescribed, has been replaced with a pair of relatively narrow way guardstrips adapted to provide individual protection for each of the pair ofspaced ways ll formed on the bed ll] of the machine. The other principaldifference lies in the fact that the individual unitary way guardstructures each function independently of the remaining structures and,more particularly, those disposed at one end of the machine are whollyindependent of those mounted on the other end of the machine. Thegeneral arrangement of parts disclosed in the modified form shown inFigures 8, 9 and 10 is similar to the structure shown in Figures 5, 6and 7, save for the fact that the utilization of the form shown inFigures 8, 9 and 10 will permit the table 12 to overtravel the way guardstructure applied to the end of the base In of the machine.

Referring specifically to the structure of the last-mentioned form ofthe invention, it will be noted that the independent way guardstructures are each unitary in form and include a frame member (5adapted to be secured to the end wall of the base Ill to form a coverfor a way guard structure receiving opening it, positioned in verticalalignment with the ends of each of the ways ii. The frame members 15each include pairs of parallelly disposed outwardly and inwardlydirected ears and flanges I! and 18, respectively. A way guard guideroller 19, disposed to lie adjacent the extremity of the way ii, isjournalled in the ears 11. Additional way guard guide rollers 80 and 8!are journalled in spaced relationship for rotary movement in the flangesit formed on the frame member 15. A pair of guide rollers 82 and B3 arerotatably journalled in a movable unit 84 comprising a yoke element 85,which includes a vertically disposed groove 86 formed in each sidethereof and arranged for cooperation with guide bars or rails 81,anchored on the flanges 18, which form a track for the movable unit 84,including the guide rollers 32 and 83. The yoke 85 includes ahorizontally disposed rib portion, which serves as a support for one endof a coil spring 88 that forms a yieldable means for normally urging theyoke 85 and associated rollers 82 and 83 away from the fixed rollers 80and 8!. The upper end of the coil spring 83 is disposed to contact a bar89, which extends across the channel formed by the flanges '43 of theframe member 15. A telescopic tube .li'l, having its ends securedrespectively to the yoke 85 and bar 89, provides a housing within whichthe spring 88 is retained.

Each of the way guard structures includes a relatively narrow flexibleway guard strip 9|, which has one end attached to a tie rod 92, securedbetween the flanges T8 of the frame member 15 and disposed at a positionabove the guide rolier The free end of the way guard strip 9! isthreaded around the rollers 83, 8|, 82 and til, through an opening 93disposed between the ears Ti and thence around the roller I9. The freeend of the way guard 91 is anchored on a pin 96 mounted in a recess 95formed on one end of a hinge plate 96. The other end of the hinge plate96 is rockably mounted on a pin 91,

carried by flanges 93 formed on a housing castintegrally with the endbracket 14, secured to the table l2 in the usual manner.

The hinge plate 96, to which one end of the flexible way guard strip 9|is attached, provides a simple and expedient method of avoiding unduewear upon the way guard 9| when the table I2 is moved to a positionbeyond the extremity of the ways II, which are co-extensive with thelength of the bed 10. As the end bracket [4 moves beyond the position inwhich the way guard Si is supported by the guide roller 79, the hingeplate 96 will ride over the surface of the roller 19 and move to asubstantially vertical position (see dotted line showing in Figure 9),wherein its lower extremity will lie below the lower surface of thetable way, so that the flexible way guard 9| will be maintained out ofcontact with the depending portion of the table way. Since the way guardSi is maintained in taut condition at all times under the action of thecoil spring 88, it is desirable to afford a positive stop for limitingthe rocking movement of the plate 96. To accomplish this end, the bottomsurface of the plate 96 is arranged to contact the surface of the endbracket l4, disposed between the flanges 98.

In each of the three forms of invention described, it will be noted thata suitable wiper element has been applied to the frame element of eachway guard structure and disposed in such relationship with the way guardreceiving opening formed therein that the wiper element will contact thecontaminated surface of the way guard to effect the removal of foreignmatter such as chips and the like which may have been deposited upon it.

It should also be noted that, in each form of the invention described inthe foregoing specification, the flexible way guard strip is arranged ina manner to insure against contact between the upper or contaminatedsurface of the guard and the lower or protective surface of the guardthat is brought into protective relationship with the normally exposedportions of the ways II. The novel method for insuring against the con-F tamination of the surface of the way guard disposed to contact the wayof the machine comprises the threading of the way guard strip over aplurality of fixed and movable guide and supporting members, in a mannerto constantly retain the adjacent runs of the guard in spacedrelationship with respect to each other. The movable guide andsupporting members are constantly urged away from the fixed guide andsupporting members under the action of a yieldable means to take up allslack in the several runs of the way guard, to insure properrelationship between the way guard and way and also to insure themaintaining of the contaminated and clean surfaces of the way guards inspaced relationship.

From the foregoing description of the illustrative embodiments of aprotective way guard structure, it will readily be seen that new andimproved unitary way guard structure has been provided for applicationto the bed of the machine and arranged in a manner to have the free endof the flexible way guard strip attached to .one end of the movable worksupport to provide a protective covering, operative at all times, toprevent the deposit of chips or other injurious foreign matter upon thefinished way surfaces of the machine, over which the table or worksupporting element is reciprocated. Each of the forms of the inventionillustrated in the accompanying drawing provides a. way guard-structure,which in no way impedes the normal operdesigned to compensate for thecomplete travel of the table or work supporting element whether the samebe within the length of the machine base or whether it is extended topermit overtravel of the ends of the table beyond the base of themachine. A further advantage of the way guard structures disclosed inthe present application lies in the fact that the guard and supportingelements are positioned in a manner to direct the path of travel of theway guard in a series of reversely directed spaced flights, where incontact between the protective surface and the contaminated surface ofthe way guard is precluded, with result that the protective surface ofthe way guard is maintained in clean condition, at all times.

While the invention has been described in considerable detail in theforegoing specification, it is to be understood that various changes maybe made in its embodiments, without departing from or sacrificing any ofthe advantages hereinafter claimed.

I claim:

1. In a machine having a base including gu de ways and a work supportmounted for sliding movement on the ways, the combination of a unitaryway guard structure arranged to provide a protective covering for thenormally exposed portions of the ways, said unitary way guard structurecomprising, a frame element for attachment .to the base of the machine,a flexible way guard carried by said frame, said way guard having oneend attached to said frame and the otherattached to the movable worksupport, a plurality of fixedly mounted way guard guide members in saidframe, a unit slidable mounted in said frame, a plurality of way guardguide members mounted in said movable unit, and yieldable means attachedat one end to said frame and at the other end to said movable unit andoperative to retain said way guard taut andcontrol the movement of saidunit in accordance with the position of the movable work support alongthe ways on the base.

2. In a machine having a base including guide ways and a work supportmounted for sliding movement on said ways, the combination of a unitaryway guard structure comprising, a frame element for attachment to thebase of the machine, a way guard and way guard support and guide membersmounted in said frame element, said way guard being formed of flexiblematerial and trained about said guard support and guide members in amanner to direct the path of said way guard in reversely directed spacedflights, a plurality of said guide members being mounted in fixedrelationship in said frame element, a movable unit mounted in said frameelement, a plurality of said guide members mounted in said movable unit,and yieldable means interposed between said frame element and saidmovable unit and operable to urge said unit and way guard guide meanscarried thereby away from said fixedly mounted support and guide memberswhereby said way guard is retained in extended taut condition andwherein a portion of said way guard is maintained in protectiverelationship with the ways throughout the movement of the work supporton the ways. 3. In a machine having a base including guide ways and awork support mounted for sliding movement on the ways, the combinationof a ation of the machine and, furthermore, each is N way guardstructure comprising, a way guard formed of flexible material adapted toprovide a protective covering for the ways, attaching means foranchoring one end of said way guard to the work support, guide means forpositioning said way guard in protective relationship with the ways,additional guide means within said structure arranged to direct the pathof travel of said way guard in a plurality of spaced paths, somerof saidadditional guide means being movable in response to movement of the worksupport, and resilient compensating mechanism interposed between saidbase and said movable guide means and operable on said movable guidemeans to yieldably retain said way'guard in extended taut condition.

4. In a machine having a base including normally exposed guide ways anda worksupport mounted for sliding movement on the ways, the combinationof a way guard structure adapted to provide protection for the normallyexposed portions of the ways, said way guard structure comprising, astrip of flexible material disposed to form a protective covering forthe ways, means for attaching one end of said way guard to the movablework support, guide and support means mounted in said structure in sucha manner that the intermediate portion of said'way guard is d rected ina path of travel having reversely directed spaced flights, said guideand support means including a plurality of rollers arranged in a mannerto provide a combination of fixed and movable elements, connecting meansbetween said movable elements, and resilient means interposed in saidconnecting means in a manner to yieldably urge said movable ele- .mentsaway from said fixed elements whereby said way guard is retained inextended taut condition at airtimeswhile permitting movement of the worksupport on the ways. i i l 5. In amachine having a baseincluding'normally exposedguideway and a work support mountedfor sl dingmovement onthew'ays,the combination of a way guardstructure comprising,a way guard formed offlexible material disposed to form a protectivecovering for the ways and having one end attached to the movable worksupport and-having its'other end anchored within said way guardstructure, guide means including a plurality of fixed and movablerollersfor en aging said way guard and directing its path of travel inreversely directed spaced flights, a unit slidably mounted in saidstructure for sup portin said movable rollers. and resilient meansoperative between said slidably mounted unit and said base to normallyurge said unit carrying said movable rollers away from said fixedrollers whereby said way guard is maintained in extended taut conditionthroughout the movement of said work support upon the ways.

6. In a machine having a base including normally exposed guide ways anda work support mounted for sliding movement on the ways, the combinationof a way guard structure comprising, a way guard formed of flexiblematerial disposed to form a protective covering for theways and havingone end attached to the movable work support and having itsotherendanchored within said way guard structure, guide means including aplurality of fixed rollers and a plural ity of movable rollers forcontacting said way guard and directing its path of travel in reverselydirected spaced flights, a movable unit carrying said movable rollers,guide means for said moveable unit, and resilient ineans operativebetween said movable unit and said base to normally urge said unit andmovable rollers away from said fixed rollers whereby movement of thework support results in displacement of said movable unit in a manner tomaintain said way guard extended and taut at all times.

7. In a machine having a base including normally exposed guide ways anda work support mounted for sliding movement on the ways, the combinationof a 'way guard structure comprising, a way guard formed of a strip offlexible material disposed to form a protective covering for the ways,guide means mounted in said structure and disposed adjacent the ends ofthe ways for directing said Way guard into the base, a movable unit insaid structure, additional way guard guide means in said unit, andyieldable means interposed between said base and said movable unit andoperative upon said unit to maintain said way guard in extended tautcondition and to compensate for movement of the work support upon heways.

8. In a machine having a base including normally exposed guide ways anda work support mounted for sliding movement on the ways, the combinationof a way guard structure comprising, a separate housing attached to eachend of the base, a pair of flexible way guards arranged for attachmentrespectively to the ends of the work support and disposed to overlie theways, support and guide members disposed adjacent the ends of the waysin each of said housings for positioning said guards over the ways anddirecting'them into the base. a movable unit in each of said housings,additional way guard guide members carried by each of said units, andyieldable means connecting said movable units and operable to retainboth of said way guards in extended taut condition and to compensate formovement of said work support on the ways.

9. The combination with a machinetool including a bas having ways and awork support mounted for sliding movement of the ways, of a way guardstructure comprising, a flexible way guard'strip attached at one end tothe work support and disposedto form a protective coverin for the ways,guide means mounted in said structure and disposed adjacent to the endof the ways for directin said way guard strip into the base of the macine tool. a movable unit in said structure. additional guide means forsaid way guard strip carri d b said movable unit, and force exerting,mechanism attached to said movable un t and to said structure andoperative upon said way guard strip to retain the same in extended tautcondition regardless of th position of the work supporting element onthe ways of the machine tool.

10. In a machine including norma ly exposed guide ways and 'a worksupport mounted for slidine movement on the ways, the combination of aunitary way guard structure conriprising a frame element for attachmentto the base of the machine, a plurality of fixed and movable way guardguide members mounted in said frame. a flexible way guard trained inextended condition over said guide members to form a plurality ofreversely directed spaced flights, said way guard having its endsanchored respectively to said frame and to said movable work support,and resilient means interposed between said fixed and said movable guidemembers and operating to urge them apart, the number of flights of saidguard multiplied by the amount of movement of said guide members beingnot less than the i2 amount of movement of the work support, wherebysaid guard is retained in extended taut condition regardless of theposition of the work support along the ways.

11. In a machine having a work support slidably mounted on normallyexposed guide ways, the combination of a way guard structure comprising,a way guard formed of a piece of flexible material having one endattached to the work support and being disposed in protectiverelationship with the guide ways and having its other end attached tosaid structure, a plurality of guide and support members for theintermediate portion of said way guard, some of said members beingmounted in fixed trunnions and others being mounted in movabletrunnions, a movable unit in said structure for supporting said movablymounted trunnions, a guide for controlling the path of travel of saidmovable unit, and resilient means interposed between said structure andsaid movable unit and operative to respond to movement of the worksupport in a manner to retain said way guard in extended taut conditionand to compensate for movement of the work support upon the guide ways.

12. In a machine having a base including guide ways and a work supportmounted for sliding movement on the ways, the combination of a way guardstructure including a pair of frame elements for application to the baserespectively adjacent the opposite ends of the ways, a flexible wayguard strip associated with each of said frame elements, one end of eachof said way guard strips being anchored to one of said frame elementsand the other end of each adapted for attachment to one of the oppositeends of the movable work support adjacent the way to be protected, guidemeans for said Way guard mounted in each of said frame elements, saidguide means including fixed and movably mounted members about which saidstrips are trained,

a movable unit in each of said frame elements 7 for supporting saidmovable members, and yieldable means connecting said units in a mannerto retain the way guard strips in extended condition and under tensionwhile the active length of each strip is varied in response to movementof the work support along the ways.

13. In a machine having a base including guide ways and a work supportmounted for sliding movement on. the ways, the combination of a unitaryway guard structure for application to the base to provide a protectivecovering for the normally exposed portions of the ways, said unitary wayguard structure comprising, a frame element for attachment to the base,a flexible way guard disposed to overlie the ways and having its endsattached respectively to said frame element and to said movable worksupport, a plurality of fixed and movable guide members carried by saidframe element over which said way guard is trained in extendedcondition, and yieldable means interposed between said movable guidemembers and said frame element to yieldably retain said way guard inextended taut condition at all times regardless of the position of themovable work support along the ways.

14. In a machine having a base including guide ways'and a work supportmounted for sliding movement on the ways, the combination of a unitaryway guard structure for application to the base of the machine toprovide a protective covering for the normally exposed portions of theways, said unitary way guard structure comprising, a frame element forattachment to the base, a flexible way guard mounted in said frameelement and having its ends attached respectively to said frame elementand the movable work support, a plurality of fixedly mounted way guardguide members carried by said frame element, a movable unit mounted insaid frame element, a plurality of way guard guide members mounted insaid movable unit, and yieldable means operating between said frameelement and said movable unit and operative on said unit to retain saidway guard in extended condition and under tension while the activelength of said way guard is varied in response to movement of the worksupport along the ways.

15. In a machine having a base including guide ways and a work supportmounted for sliding movement along the ways, the combination of aunitary way guard structure arranged to provide a protective coveringfor the normally exposed portions of the ways, said unitary way guardstructure comprising, a frame for attachment to the base, a plurality ofway guard guide memhere including fixed and movable members mounted insaid frame, a flexible way guard strip trained about said fixed andmovable way guard guides in a manner to retain said guard in extendedcondition within said frame, said way guard strip having one endanchored in said frame and the other end attached to the movable worksupport in a position to form a protective covering for the ways, andforce exerting mechanism operative upon said movable guide members tourge them away from said fixed guide members in manner to retain saidflexible way guard taut and to compensate for movement of the worksupport along the ways of the machine.

16. In a machine having a base including guide ways and a work supportmounted for sliding movement along the ways, the combination of aunitary way guard structure arranged to provide a protective coveringfor the exposed portions of the ways, said unitary way guard structurecomprising, a frame element for attachment to the base of the machine, aplurality of way guard guide members mounted in spaced relationship insaid frame element, some of said members being fixedly mounted andothers being movably mounted, a flexible way guard strip trained aboutsaid members to follow a tortuous path including reversely directedspaced flights, means for anchoring the ends of said flexible Way guardstrip respectively to said frame element and to said movable worksupport in a position to form a protective covering for the ways, andforce exerting mechanism o erative upon said movable way guard guidemembers at all times in manner to retain said way guard in extended tautcondition. regardless of the position of said work sup port along theways.

17. In a machine having a base including guide ways and a work supportmounted for sl ding movement along the ways, the combination of aunitary way guard structure adapted to provide a protective covering forthe normally exposed portions of the ways, said unitary way guardstructure comprising, a frame for attachment to the base of the machine.a plurality of way guard guide members includ ng a bank of fixed and abank of movable members mounted in said frame, said fixed and movablemembers being positioned respectively in spaced relationship. a flexibleway guard strip trained about said guide members in extended condition,and a force exerting mechanism operative upon said movable guide membersin manner to retain said 14 way guard taut and permit movement of thework support along the ways of the machine.

18. In a machine having a base including guide Ways and a work supportmounted for sliding movement on the ways, the combination of a unitaryway guard structure arranged to provide a protective covering for thenormally exposed portions of the ways, said unitary way guard structurecomprising, a frame adapted for attachment to the end of the base toform a component part thereof, a plurality of fixedly mounted way guardguide members positioned in spaced relationship in said frame, aplurality of movable way guard guide members positioned in spacedrelationship in said frame, a flexible way guard strip trained aboutsaid fixed and movable guide members in a manner to effect the housingof its extended length within a relatively small space, and forceexerting mechanism attached to said movable way guard guide members andoperative thereon to force them away from said fixed guide members, saidforce exerting mechanism serving to retain said way guard in extendedtaut condition and to permit movement of said guide members tocompensate for movement of the work support along the ways.

19. In a machine having a base including guide ways and a work supportmounted for sliding movement along the ways, the combination of a wayguard structure arranged to provide a protective covering for thenormally exposed portions of the ways, said way guard structurecomprising, a frame adapted for attachment to the end of the base toform a component part thereof, a plurality of way guard guide membersmounted in said frame, a flexible way guard strip having its endsattached respectively to said frame and the movable work support andhaving its intermediate portion trained about said guide members, amovable unit supporting a plurality of said guide members, and a yilding force exerting mechanism operatively attached to said movable unitand acting in direction to provide a means for yieldably retaining saidway guard in taut extended condition and permitting motion of saidmovable element to effect the advance or retraction of said way guard inresponse to movement of the work support along the ways.

20. In a machine having a base including guide ways and a work supportmounted for sliding movement along the ways, the combination of a wayguard structure arranged to provide a protective covering for thenormally exposed portions of the ways, said way guard structurecomprising, a way guard housing adapted for attachment to the end ofsaid base to form a component part thereof, a plurality of fixed andmovable way guard guide members mounted in said housing, said fixed andmovable guide members being respectively mounted in spaced relationship,a flexible way guard strip having one end attached to the work supportin a position to form a protective covering for the ways and its otherend anchored in said guard housing with the intermediate portion thereoftrained in extended condition about said guide members, and a resilientforce exerting compensating mechanism attached to said guard housing andto said movable guide members and operative to control their movement inresponse to movement of the work support in a manner to retain said Wayguard in extended taut condition at all times.

21. In a machine tool having a bed presenting bearing ways and acarriage slidably mounted on said ways, guards for said ways comprisingflexible guard strips extending from each end of said carriage alongsaid ways and over the ends of said bed, a plurality of guide rollersrotatably mounted invfixed positions at each end of said bed, a rollersupporting unit slidably mounted at each end of said bed for movementtoward or irom said fixed position rollers, a plurality of guide rollersrotatably mounted in said bodily movable unit, said guard strips beingthreaded over said fixed rollers and said movable rollers alternately,and resilient force exerting means operatively connectedto urge saidmovable rollers away from said fixed rollers for maintaining said stripstaut while permitting them to be paid out or retracted in conformitywith movement of said carriage along said Ways.

22. In a machine tool having a bed presenting bearing ways and acarriage slidably mounted on said ways, a hinge plate pivotallyconnected to said carriage over each of said ways at each end of saidcarriage, flexible guard strips each pivotally connected at one end toone of said hinge 16 plates and disposed to extend over and protect saidways, and means to take in and pay out said guard strips in accordancewith movements of said carriage along said ways, the arrangements beingsuch that when said carriage overruns said Ways said hinge plates on theoverrunning end pivot downward to support said guard strips out ofcontact with the lower surface of said carriage.

JOSEPH B. ARMITAGE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 848,578 Thelin Mar. 26, 19071,679,912 Mondloch Aug. 7, 1928 1,895,122 Benedict Jan. 24, 19331,937,985 Schnuck Dec. 5, 1933 2,190,213 Meyer Feb. 13, 1940 2,246,199Caldwell June 17, 1941

